JP2012114469A - Lithographic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lithographic apparatus in which liquid can be drained through a gap between, for example, an edge of an object and a substrate table on which the object is disposed.SOLUTION: A liquid immersion lithographic apparatus includes a drain configured to drain liquid through a gap between an edge of a substrate and a substrate table on which the substrate is supported. The drain comprises: means for feeding the liquid to the drain regardless of a position of the substrate table; and/or means for saturating gas in the drain. These means reduce fluctuation of heat loss due to evaporation of the liquid in the drain.

Description

The present invention relates to a lithographic apparatus and a method for manufacturing a device.

A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such cases, a patterning device, alternatively referred to as a mask or reticle, can be used to generate a circuit pattern to be formed on an individual layer of the IC. This pattern can be transferred onto a target portion (eg comprising part of, one, or several dies) on a substrate (eg a silicon wafer). The pattern is usually transferred by imaging onto a layer of radiation sensitive material (resist) provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned. A conventional lithographic apparatus scans a substrate in parallel or anti-parallel to a predetermined direction ("scan" direction) and a so-called stepper that irradiates each target portion by exposing the entire pattern to the target portion at once. However, a so-called scanner is provided that irradiates each target portion by scanning the pattern with a radiation beam in a predetermined direction (“scan” direction). It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.

In lithographic projection apparatus, it has been proposed to immerse the substrate in a liquid having a relatively high refractive index, such as water, so as to fill a space between the final element of the projection system and the substrate. The point is to allow smaller features to be imaged. This is because the exposure radiation has a shorter wavelength in the liquid. (The effect of the liquid can also be thought of as increasing the effective NA of the system (if supported by the lens) and increasing the depth of focus.) Others such as water with solid particles (eg quartz) floating Immersion liquids have been proposed.

[0004] However, immersing the substrate, or the substrate and substrate table in a bath of liquid (see, eg, US Pat. No. 4,509,852, which is incorporated herein by reference in its entirety) accelerates during scan exposure. There is also a large lump of liquid that should be. This requires an additional motor or a more powerful motor, and turbulence in the liquid can cause undesirable and unpredictable effects.

[0005] One proposed solution is that the liquid supply system uses a liquid containment system to provide liquid only between the local area of the substrate and the final element of the projection system and the substrate. (The substrate typically has a larger surface area than the final element of the projection system). One known method for arranging this is disclosed in PCT patent publication WO 99/49504, which is hereby incorporated by reference in its entirety. As illustrated in FIGS. 2 and 3, liquid is supplied onto the substrate by at least one inlet IN, preferably along the direction of movement of the substrate relative to the final element, and at least one after passing under the projection system. Removed by two outlets OUT. That is, when the substrate W is scanned under the element in the −X direction, liquid is supplied on the + X side of the element and taken up on the −X side. FIG. 2 schematically shows a configuration in which liquid is supplied via an inlet IN and is taken up on the other side of the element by an outlet OUT connected to a low pressure source. In the illustration of FIG. 2, the liquid is supplied along the direction of movement of the substrate relative to the final element, although this need not be the case. Various orientations and numbers of inlets and outlets arranged around the final element are possible, an example is illustrated in FIG. 3, where four sets of inlets and outlets on each side are regular around the final element. Provided in pattern.

[0006] A further solution in immersion lithography with a localized liquid supply system is illustrated in FIG. The liquid is supplied by two groove inlets IN on either side of the projection system PL and is removed by a plurality of separate outlets OUT arranged radially outside the inlet IN. The inlets IN and OUT can be arranged in a plate with a hole in the center and through which the projected projection beam passes. The liquid is supplied by one groove inlet IN on one side of the projection system PL and removed by a plurality of separate outlets OUT on the other side of the projection system PL, so that between the projection system PL and the substrate W A liquid thin film flow occurs. The choice of which combination of inlets IN and outlets OUT to use can be determined by the direction of movement of the substrate W (other combinations of inlets IN and outlets OUT are inactive).

[0007] European patent application publication EP 1420300 and US patent application publication US 2004-0136494 (currently patented as US Pat. No. 7,193,232) disclose the concept of a twin or dual stage immersion lithography apparatus. ing. Such an apparatus is provided with two tables for supporting the substrate. Leveling measurement is performed on the table at the first position without immersion liquid, and exposure is performed on the table at the second position where immersion liquid is present. Alternatively, the device may have only one table.

[0008] Handling of immersion liquid in a lithographic apparatus involves one or more problems of liquid handling. There is usually a gap between an object, such as a substrate and / or sensor, and a substrate table around the edge of the object (eg, substrate). US Patent Application Publication No. US 2005-0264778 fills the gap with material in order to avoid bubble inclusions when the gap passes under the liquid supply system and / or to remove all liquid that actually enters the gap. Or providing a liquid or low pressure source to intentionally fill the gap with liquid.

[0009] For example, it is desirable to remove the liquid from the gap between the edge of the object and the substrate table on which the object is placed. The object may be a substrate, a sensor, a closed plate, or the like.

[0010] According to an aspect of the invention,
A substrate table for holding the substrate;
A drain in the substrate table that receives a first liquid that leaks between the edge of the object on the substrate table and the substrate table in use;
An outlet to the drain for flowing liquid and / or gas from the drain;
A liquid supply device that actively supplies the second liquid to the drain regardless of the position of the substrate table;
A lithographic apparatus comprising:

[0011] According to an aspect of the invention,
A substrate table for holding the substrate;
A liquid supply system for providing a liquid in a local area of the substrate, the substrate table and / or the object on the substrate table between the substrate, the substrate table and / or the object and the projection system;
A drain in the substrate table that, in use, traps liquid leaking between the edge of the substrate and / or object and the substrate table;
An outlet connected to the low pressure source and the drain to remove liquid and / or gas from the drain;
A saturator that saturates all gases entering and exiting the drain with liquid,
A lithographic apparatus comprising:

[0012] According to an aspect of the present invention, a patterned radiation beam is projected through a liquid onto a substrate, and liquid leaking between the edge of the object and the substrate table holding the substrate is collected in the drain, and the liquid from the drain And a method of manufacturing a device comprising saturating a gas flowing into and / or from the drain.

[0013] Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings. Corresponding reference characters indicate corresponding parts in the drawings.

[0014] Figure 1 depicts a lithographic apparatus according to an embodiment of the invention. [0015] FIG. 1 shows a liquid supply system for use in a lithographic projection apparatus. [0015] FIG. 1 shows a liquid supply system for use in a lithographic projection apparatus. [0016] Figure 6 depicts another liquid supply system for use in a lithographic projection apparatus. [0017] FIG. 1 illustrates a local area liquid supply system. 1 is a cross-sectional view illustrating a substrate table according to an embodiment of the present invention.

[0019] Figure 1 schematically depicts a lithographic apparatus according to one embodiment of the invention. This device

[0020] an illumination system (illuminator) IL configured to condition a radiation beam B (eg UV radiation or DUV radiation);

[0021] A support structure (eg, a mask table) configured to support the patterning device (eg, mask) MA and connected to a first positioner PM configured to accurately position the patterning device according to certain parameters MT,

[0022] A substrate table (eg, a wafer table) WT configured to hold a substrate (eg, a resist-coated wafer) W and connected to a second positioner PW configured to accurately position the substrate according to specific parameters. When,

[0023] A projection system (eg, a refractive projection lens system) configured to project a pattern imparted to the radiation beam B by the patterning device MA onto a target portion C (eg, including one or more dies) of the substrate W. Including PS.

[0024] The illumination system includes various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic, etc. optical components, or any combination thereof, for directing, shaping or controlling radiation. You may go out.

The support structure holds the patterning device in a manner that depends on the orientation of the patterning device, the design of the lithographic apparatus, and the like, for example, whether or not the patterning device is held in a vacuum environment. The support structure can use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device. The support structure may be a frame or a table, for example, and may be fixed or movable as required. The support structure may ensure that the patterning device is at a desired position, for example with respect to the projection system. Any use of the terms “reticle” or “mask” herein may be considered synonymous with the more general term “patterning device.”

[0026] As used herein, the term "patterning device" is used broadly to refer to any device that can be used to pattern a cross-section of a radiation beam so as to generate a pattern on a target portion of a substrate. Should be interpreted. It should be noted here that the pattern imparted to the radiation beam may not exactly correspond to the desired pattern in the target portion of the substrate, for example if the pattern includes phase shift features or so-called assist features. In general, the pattern imparted to the radiation beam corresponds to a special functional layer in a device being created in the target portion, such as an integrated circuit.

[0027] The patterning device may be transmissive or reflective. Examples of patterning devices include masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in lithography, and include mask types such as binary masks, Levenson phase shift masks, attenuated phase shift masks, and various hybrid mask types. It is. As an example of a programmable mirror array, a matrix array of small mirrors is used, each of which can be individually tilted to reflect the incoming radiation beam in a different direction. The tilted mirror imparts a pattern to the radiation beam reflected by the mirror matrix.

[0028] As used herein, the term "projection system" refers appropriately to other factors such as, for example, the exposure radiation used or the use of immersion liquid or the use of a vacuum, eg refractive optical system, reflective optics. It should be construed broadly to cover any type of projection system, including systems, catadioptric optical systems, magneto-optical systems, electromagnetic optical systems and electrostatic optical systems, or any combination thereof. Any use of the term “projection lens” herein may be considered as synonymous with the more general term “projection system”.

The apparatus shown here is of a transmissive type (for example using a transmissive mask). Alternatively, the device may be of a reflective type (for example using a programmable mirror array of the type mentioned above or using a reflective mask).

[0030] The lithographic apparatus may be of a type having two (dual stage) or more substrate tables (and / or two or more mask tables). In such “multi-stage” machines, additional tables can be used in parallel, or one or more other tables can be used for exposure while one or more tables perform the preliminary process can do.

[0031] Referring to FIG. 1, the illuminator IL receives a radiation beam from a radiation source SO. The radiation source and the lithographic apparatus may be separate components, for example when the radiation source is an excimer laser. In such a case, the radiation source is not considered to form part of the lithographic apparatus, and the radiation beam is emitted from the source SO by means of a beam delivery system BD, for example equipped with a suitable guiding mirror and / or beam expander. Passed to IL. In other cases the source may be an integral part of the lithographic apparatus, for example when the source is a mercury lamp. The radiation source SO and the illuminator IL may be referred to as a radiation system together with a beam delivery system BD as required.

The illuminator IL may include an adjuster AD that adjusts the angular intensity distribution of the radiation beam. Typically, the outer and / or inner radius range (commonly referred to as σ-outer and σ-inner, respectively) of the intensity distribution at the illuminator pupil plane can be adjusted. The illuminator IL may include various other components such as an integrator IN and a capacitor CO. Alternatively, the radiation beam may be adjusted using an illuminator so that desired uniformity and intensity distribution can be obtained across the cross section.

[0033] The radiation beam B is incident on the patterning device (eg, mask) MA, which is held on the support structure (eg, mask table) MT, and is patterned by the patterning device. The radiation beam B passes through the patterning device MA and passes through a projection system PS that focuses the beam onto a target portion C of the substrate W. With the help of the second positioner PW and the position sensor IF (eg interferometer device, linear encoder or capacitive sensor), the substrate table WT can be moved precisely to position the various target portions C, for example in the path of the radiation beam B. . Similarly, for the path of the radiation beam B using a first positioner PM and another position sensor (not explicitly shown in FIG. 1), eg after mechanical retrieval from a mask library or during a scan. Thus, the patterning device MA can be accurately positioned. In general, the movement of the support structure MT can be realized using a long stroke module (coarse positioning) and a short stroke module (fine positioning) that form part of the first positioning device PM. Similarly, movement of the substrate table WT can be realized with the aid of a long stroke module and a short stroke module forming part of the second positioner PW. In the case of a stepper (as opposed to a scanner) the support structure MT may be connected only to a short stroke actuator or fixed. Patterning device MA and substrate W may be aligned using patterning device alignment marks M1, M2 and substrate alignment marks P1, P2. The substrate alignment mark as shown occupies a dedicated target position, but may be arranged in a space between target portions (referred to as a scribe lane alignment mark). Similarly, in situations in which a plurality of dies are provided on the patterning device MA, patterning device alignment marks may be placed between the dies.

The illustrated lithographic apparatus can be used in at least one of the following modes:

[0035] In step mode, the support structure MT and the substrate table WT are basically kept stationary, while the entire pattern imparted to the radiation beam is projected onto the target portion C at one time (ie one stationary operation). exposure). Next, the substrate table WT is moved in the X and / or Y direction so that another target portion C can be exposed. In the step mode, the size of the target portion C on which an image is formed in one still exposure is limited by the maximum size of the exposure field.

[0036] 2. In scan mode, the support structure MT and the substrate table WT are scanned synchronously while a pattern imparted to the radiation beam is projected onto a target portion C (ie, one dynamic exposure). The speed and direction of the substrate table WT relative to the support structure MT can be determined by the enlargement (reduction) and image reversal characteristics of the projection system PS. In the scan mode, the maximum size of the exposure field limits the width of the target portion (in the non-scan direction) in one dynamic exposure, and the length of the scan operation determines the height of the target portion (in the scan direction). .

[0037] 3. In another mode, the support structure MT is held essentially stationary, holding the programmable patterning device, and projecting the pattern imparted to the radiation beam onto the target portion C while moving or scanning the substrate table WT. . In this mode, a pulsed radiation source is typically used to update the programmable patterning device as needed each time the substrate table WT is moved or between successive radiation pulses during a scan. This mode of operation can be readily applied to maskless lithography that utilizes programmable patterning device, such as a programmable mirror array of a type as referred to above.

[0038] Combinations and / or variations on the above described modes of use or entirely different modes of use may also be employed.

[0039] Although one or more embodiments of the present invention may be used with any type of liquid supply system, the design discussed herein is a local area liquid as illustrated in FIG. Optimized for use with supply systems. In this type of liquid supply system, liquid is only provided to a small area of the entire top surface of the substrate at any given time. This is an example to briefly explain the operation of the local area liquid supply system.

[0040] Referring to FIG. 5, a local area liquid supply system includes a liquid supply system having a liquid containment structure that extends along at least a portion of the boundary of the space between the final element of the projection system and the substrate table. Prepare. The liquid containment structure is substantially stationary in the XY plane with respect to the projection system, but there may be some relative movement in the Z direction (the direction of the optical axis). In an embodiment, a seal is formed between the liquid containment structure and the surface of the substrate, and may be a contactless seal such as a gas seal.

[0041] The liquid containment structure 12 at least partially confine the immersion liquid in the space 11 between the final element of the projection system PL and the substrate W. A contactless seal 16 of the substrate can be formed around the image field of the projection system so that liquid is contained within the space between the substrate surface and the final element of the projection system. This space is at least partly formed by the liquid containment structure 12 which is located below and surrounds the final element of the projection system PL. Liquid can be brought into the space within the liquid containment structure 12 below the projection system by the liquid inlet 13 and removed by the liquid outlet 13. The liquid containment structure 12 extends slightly above the final element of the projection system and the liquid level rises above the final element so that a liquid buffer is provided. The liquid containment structure 12 may have an inner circumference whose upper end may closely match the shape of the projection system or its final element in embodiments, for example circular. At the bottom, the inner circumference closely matches the shape of the image field, for example rectangular, but this need not be the case.

[0042] The liquid is confined in the space 11 during use by a gas seal 16 formed between the bottom of the liquid containment structure 12 and the surface of the substrate W. The gas seal is formed of a gas such as air or synthetic air, but in an embodiment is N2 or another inert gas, and under pressure, through the inlet 15 into the gap between the liquid containment structure 12 and the substrate. Provided and extracted via outlet 14. The overpressure to the gas inlet 15, the level of vacuum to the outlet 14, and the gap geometry are configured so that there is a high velocity gas flow inward to contain the liquid. These inlets / outlets may be annular grooves surrounding the space 11, and the flow of gas 16 is effective to contain the liquid in the space 11. Such a system is disclosed in US Patent Application Publication No. US 2004-0207824.

[0043] Other solutions are possible, and one or more embodiments of the invention are equally applicable thereto. For example, instead of the gas seal 16, it is possible to have a single phase extractor that extracts only liquid. On the radially outer side of such a single phase extractor there may be one or more features that generate a gas flow that helps confine the liquid in the space. One such type of feature may be a so-called gas knife that causes a thin jet of gas to face down onto the substrate W. While the substrate is in scanning motion under the projection system and the liquid supply system, hydraulic and hydrostatic pressures can be generated, resulting in downward pressure on the liquid toward the substrate.

[0044] In the local area liquid supply system, the substrate W moves below the projection system PL and the liquid supply system and forms an image on the edge of the substrate W, or forms an image on a sensor on the substrate table, or replaces the substrate. If the substrate table is to be moved so that a dummy substrate or so-called closed plate can be placed below the liquid supply system in order to be able to carry out the process, the edge of the substrate W passes under the space 11 and the liquid is transferred to the substrate W And leaks into the gap between the substrate table WT. This liquid can be forced by hydraulic or hydrostatic pressure or the power of a gas knife or other gas flow generator.

[0045] One or more embodiments of the present invention will be described below with respect to providing a drain around the edge of the substrate W, but one or more embodiments may provide liquid supply, for example, during substrate replacement. One or other disposed on a substrate table including but not limited to a closed plate and / or one or more sensors used to maintain liquid in the liquid supply system by attaching to the bottom of the system It is equally applicable to other objects. Accordingly, the following reference to the substrate W should be considered synonymous with any other object such as a sensor or a closed plate.

[0046] FIG. 6 illustrates an embodiment of the present invention. FIG. 6 is a cross-sectional view of the substrate table WT and the substrate W. A gap 5 exists between the edge of the substrate W and the edge of the substrate table WT. When imaging on the edge of the substrate W, or at any other time, such as when the substrate W first moves under the projection system PS (as described above), the edge of the substrate W and the substrate table WT The gap 5 between the edges passes below a space 11 filled with liquid, for example by a liquid supply system 12. As a result, liquid from the space 11 enters the gap.

In order to deal with the liquid entering the gap, at least one drain 10, 20 is provided at the edge of the substrate W to remove all liquid entering the gap 5. In the embodiment of FIG. 6, two drains 10, 20 are shown, but there may be only one drain or there may be more than two drains. Each of the drains 10 and 20 has, for example, an annular shape so as to surround the entire circumference of the substrate W.

[0048] The main function of the first drain 10 is to prevent bubbles from entering the liquid 11 of the liquid supply system 12. All such bubbles can adversely affect the imaging of the substrate W. A second drain 20 is provided to prevent liquid from flowing from the gap 5 below the substrate W, preventing it from effectively releasing the substrate W from the substrate table WT after imaging. As is conventional, the substrate W is held by a pimple table 30 having a plurality of protrusions 32. The low pressure applied between the substrate W and the substrate table WT by the pimple table 30 ensures that the substrate W is securely held in place. However, if liquid enters between the substrate W and the pimple table 30, this can cause difficulties, particularly when the substrate W is unloaded. Providing the second drain 20 reduces or eliminates problems that may occur due to the liquid flowing under the substrate W.

[0049] Both the first and second drains 10, 20 remove liquid by low pressure. That is, both drains are connected to a low pressure source via outlets 142 and 242. This low pressure source effectively removes all liquid that entered the individual drains. However, the low pressure source also effectively draws gas through the individual drains from outside the gap 5 on the substrate table WT (or from the pimple table 30 in the case of the second drain 20) and out through the outlet. This liquid and gas flow is not constant during use of the immersion apparatus. If there is a possibility of liquid entering the gap 5, measures can be taken to connect only the outlets 142, 242 to the low pressure source, but the amount of gas and / or liquid passing through the drains 10, 20 changes. There is a risk that a non-uniform heat load is applied to the substrate table WT. As a result of this temporarily non-uniform flow of gas and liquid, the evaporation rate of the liquid in the drains 10, 20 is different, thereby varying the heat loss generated by the drains 10, 20 during exposure of a batch of substrates. Resulting in. The thermal loss varies in this way during the exposure because the substrate table WT is arranged only so that the edge of the substrate W is below the space 11 during a specific time depending on the path of exposure. It is. Thus, in the first substrate of a batch of substrates, the evaporation load around the substrate is at a different position than the subsequent substrates. Furthermore, since there is a delay in the timing of delivering the substrate from the track at the start of a new batch, the evaporation loss changes due to the drying of the drains 10, 20 (and thus the reduction in evaporation).

[0050] In order to mitigate the above-described changes in heat loss applied by the drains 10, 20, regardless of the position of the substrate table (ie, regardless of whether the edge of the substrate is below the space 11) Measures are taken to remain substantially constant. The way to achieve this can be seen in two separate ways. First, this gas is the same (type) of liquid that the liquid supply device 12 uses so that it cannot cause evaporation if it passes over the liquid in the drain. Can be considered to ensure that it is saturated or at least nearly saturated. Second, it can be thought of as providing a continuous flow of liquid (immersion) through the drains 10, 20, thereby making the heat loss uniform over time.

[0051] Details of the structure of each drain will be described in detail below. However, the principle of the present invention is that any type of immersion apparatus in which the use of the apparatus is provided with a fluctuating flow of liquid and / or gas through it, thereby varying the amount of evaporation and varying the heat load. It should be understood that the present invention can also be applied to other drains. The means for providing liquid to drains 10, 20 or saturating the gas in the drain can be at any location as long as it is compatible with the functions as described above and there is no detrimental interference with other components of the device. It is also recognized that

In the drain 10 disposed on the radially outer side of the drain 20, a flow path 110 communicates from the gap 5 between the substrate W and the substrate table WT to the first chamber 120. Both the channel 110 and the chamber 120 are annular, for example. The channel 110 is preferably in the form of a slit. That is, it is relatively narrow compared to the height. The second chamber 140 is in fluid communication with the first flow path 120 through the plurality of through holes 130. The through holes 130 are desirably evenly spaced around the substrate. An outlet 142 connected to a low pressure source is in fluid communication with the bottom of the second chamber 140. As will be appreciated, the shape of the chambers 120, 140 may vary in cross-section from that illustrated in FIG. 6 for details regarding the various cross-sectional shapes that function and the surface characteristics of various aspects of the desired chamber. See the disclosures of Japanese Patent Application Publication No. 2007-072118 and US Patent Application No. 11 / 390,427 filed March 28, 2006.

[0053] Liquid inlets 122, 144 are provided in each chamber 120,140. These liquid inlets 122, 144 can provide a spray of liquid as shown, or provide a continuous flow of liquid or something in between (eg, a drop of a constant drop). In this way, the gas in the individual chambers can be saturated (or nearly saturated) or provide a continuous flow of liquid through each chamber.

[0054] It will be appreciated that only one of the chambers 120, 140 can be provided with a liquid inlet 122, 144, or alternatively or additionally a liquid inlet can be provided in the flow path 110 or in the gap 5. . If a liquid inlet is provided in the gap 5, one liquid inlet is sufficient for both the first and second drains 10, 20. In this description, when referring to a single liquid inlet, it is recognized that it means that there is a single liquid inlet in cross section. Of course, the liquid inlets 122, 144 can be provided as continuous (annular) grooves or as separate inlets around the drain.

[0055] Next, the second drain 20 will be described. The outlet 242 of the second drain 20 is maintained at a low pressure (eg 0.6 bar) slightly higher than the low pressure (eg 0.5 bar) of the pimple table 30. Thereby, the gas flow from the pimple table 30 to the outlet 242 from the gap 5 is secured.

As can be seen in the figure, two protrusions 210 and 220 are provided below the substrate W. The radially outer protrusion 210 is a so-called “wet seal”, and is likely to have immersion liquid passing between it and the bottom surface of the substrate W. The radially inner projection 220 is a dry seal, and there is a high possibility that only gas passes between it and the substrate W.

[0057] Between the two protrusions 210, 220 there is a flow path 230 leading to the chamber 240. Chamber 240 is in fluid communication with an outlet 242 connected to a low pressure source. The chamber 240 is provided with a liquid inlet 244. The liquid inlet 244 acts as a mechanism for saturating the inside of the chamber 240 with a gas or a mechanism for continuously supplying liquid to the outlet 242 regardless of the presence or absence of the space 11 on the gap 5.

[0058] In an alternative configuration, for the low pressure of the pimple table 30 of 0.475 bar, the outlet 242 is only maintained at a low pressure of 0.5 bar. In this case, the liquid can be on the inner protrusion 220 and the combination of the pressure differential and the capillary force of the liquid maintains the liquid between the inner protrusion 220 and the substrate W and moves to the pimple table 30. It is enough not to let it. To maintain this pressure difference with varying resistance to the gas flowing through the external protrusion 210 (depending on whether liquid is present or not between the external protrusion 210 and the substrate), a substrate table The pressure is adjusted by the outer squeeze net. As a result, the largest part of the liquid evaporation and thus the heat load occurs in this squeezed net. Therefore, only a portion with small evaporation is generated in the substrate table WT below the substrate W. The dependence of the heat loss on the wetting history of this final part is forced wetting and can be adjusted preferably at the exit between the two protrusions 210, 220 as described above.

[0059] As can be seen in the figure, the dependence of the wetting history on the thermal load of the extractors of the immersion apparatus is determined by providing immersion liquid to these extractors constantly (ie regardless of the substrate table). Can be adjusted. This principle also works by providing the liquid in a gaseous state (ie, a saturated or humidified gas). This principle can also be used in other extractors of immersion machines that have the same problem. An example is an extractor used in a liquid supply system that supplies liquid between the final element of the projection system and the substrate (examples are shown in FIGS. 2 to 5). In some cases, the heat loss caused by the extractor fluctuates and the difficulty can be alleviated by providing the extractor with a liquid or humidified gas (eg, during substrate replacement).

[0060] Although the text specifically refers to the use of a lithographic apparatus in the manufacture of ICs, it will be appreciated that the lithographic apparatus described herein has other uses. For example, this is an integrated optical device, guidance and detection patterns for magnetic domain memory, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, and the like. In light of these alternative applications, the use of the terms “wafer” or “die” herein are considered synonymous with the more general terms “substrate” or “target portion”, respectively. It will be apparent to those skilled in the art. The substrate described herein may be processed before or after exposure, eg, with a track (usually a tool that applies a layer of resist to the substrate and develops the exposed resist), metrology tool, and / or inspection tool. Can do. Where appropriate, the disclosure herein may be applied to these and other substrate processing tools. In addition, the substrate can be processed multiple times, for example to produce a multi-layer IC, so the term substrate as used herein can also refer to a substrate that already contains multiple processed layers.

[0061] While the above specifically refers to the use of embodiments of the present invention in the context of optical lithography, the present invention can also be used in other applications, such as imprint lithography, if the situation allows, It is understood that the present invention is not limited to optical lithography. In imprint lithography, the pattern generated on the substrate is defined by the microstructure of the patterning device. The patterning device microstructure is pressed against a layer of resist supplied to the substrate, after which the resist is cured by electromagnetic radiation, heat, pressure or a combination thereof. The patterning device is moved away from the resist, leaving a pattern after the resist is cured.

[0062] As used herein, the terms "radiation" and "beam" include not only particle beams such as ion beams or electron beams, but also ultraviolet (UV) radiation (eg, 365 nm, 248 nm, 193 nm, 157 nm or All types of electromagnetic radiation are encompassed, including wavelengths at or around 126 nm) and extreme ultraviolet light (EUV) radiation (eg having a wavelength in the range of 5 nm to 20 nm).

[0063] The term "lens" refers to any of various types of optical components, or combinations thereof, including refractive, reflective, magnetic, electromagnetic and electrostatic optical components, as the situation allows.

[0064] While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. For example, the present invention provides a computer program that includes one or more sequences of machine-readable instructions that describe a method as disclosed above, or a data storage medium (eg, semiconductor memory, etc.) that stores such a computer program. Magnetic or optical disk).

[0065] One or more embodiments of the present invention are not exclusive to any immersion lithographic apparatus, in particular the type described above, even if the immersion liquid is provided in the form of a bath, It can be applied even if provided only to the surface area. A liquid supply system as contemplated herein should be interpreted broadly. In certain embodiments, this may be a mechanism or combination of structures that provides liquid to the space between the projection system and the substrate and / or substrate table. This includes one or more structures, one or more liquid inlets, one or more gas inlets, one or more gas outlets and / or one or more liquid outlets that provide liquid to the space. Combinations can be provided. In embodiments, the surface of the space is part of the substrate and / or substrate table, the surface of the space completely covers the surface of the substrate and / or substrate table, or the space surrounds the substrate and / or substrate table. Can do. The liquid supply system may further include one or more elements that optionally control the position, quantity, quality, shape, flow rate, or any other characteristic of the liquid.

[0066] The immersion liquid used in the apparatus may have various compositions according to the desired properties and wavelength of the exposure radiation used. In the case of an exposure wavelength of 193 nm, ultrapure water or an aqueous formulation can be used, and for this reason, the immersion liquid is sometimes referred to as water, and is related to water such as hydrophilicity, hydrophobicity, and humidity. Terminology can be used.

[0067] The descriptions above are intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below.

Claims (20)

A substrate table for holding the substrate;
A drain in the substrate table that receives a first liquid that leaks between an edge of an object on the substrate table and the substrate table in use;
An outlet to the drain for flowing liquid and / or gas from the drain;
A liquid supply device that actively supplies the second liquid to the drain regardless of the position of the substrate table;
A lithographic apparatus comprising:   The apparatus of claim 1, wherein the outlet is connected to a low pressure source to generate a flow of gas that enters the drain from outside the drain and exits through the outlet.   The apparatus of claim 1, wherein the liquid supply device is configured to supply liquid at a flow rate and configuration that substantially saturates the gas flowing through the outlet.   The apparatus of claim 1, comprising at least two of the drains, wherein the first of the drains is disposed second radially inward of the drain.   The apparatus of claim 1, wherein the drain comprises a slit leading to the first chamber.   The apparatus of claim 5, wherein the liquid supply device provides the second liquid to the first chamber.   The apparatus of claim 5, wherein the drain further comprises a second chamber connected to the first chamber by a through hole.   The apparatus of claim 7, wherein the liquid supply device provides the second liquid to the second chamber.   The apparatus of claim 5, wherein the slit makes the first chamber in fluid communication with an edge of the substrate.   The apparatus according to claim 1, wherein the liquid supply apparatus supplies the second liquid as a gas.   The apparatus according to claim 1, wherein the object is a substrate, a sensor or a cover plate.   The apparatus of claim 1, wherein the first liquid and the second liquid are the same type of liquid. A substrate table for holding the substrate;
A liquid supply system for providing a liquid in a local area of the substrate, the substrate table and / or an object on the substrate table between the substrate, the substrate table and / or the object and a projection system;
A drain in the substrate table that, in use, confines liquid leaking between the substrate and / or object edge and the substrate table;
An outlet connected to the low pressure source and the drain to remove liquid and / or gas from the drain;
A saturator that saturates all gases entering and exiting the drain with a liquid;
A lithographic apparatus comprising:   The apparatus of claim 13, wherein the saturator saturates the gas with a liquid that is the same as the liquid supplied by the liquid supply system.   The apparatus of claim 13, wherein the saturator operates independent of the position of the substrate table.   The apparatus of claim 13, wherein the object is a sensor or a cover plate.   Projecting a patterned beam of radiation through the liquid onto the substrate, collecting the liquid leaking between the edge of the object and the substrate table holding the substrate in the drain, removing the liquid from the drain, and extending to the drain A device manufacturing method comprising saturating a gas flowing from a drain.   The method of claim 17, wherein saturating a gas flowing to and / or from the drain comprises supplying a liquid to the gas flowing to and / or from the drain.   The method of claim 18, wherein the object is a substrate, a sensor or a cover plate.   20. A method according to claim 19, comprising supplying a liquid in the form of a gas to and / or to the gas flowing from and / or to the drain.

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